Compositions having enhanced deposition of a topically active compound on a surface

Abstract

Topically active compositions having enhanced effectiveness are disclosed. The compositions contain a topically active compound, an anionic surfactant, a hydric solvent, a hydrotrope, an optional cosurfactant, and water, wherein a percent saturation of the topical active compound of the composition is at least 25%. The compositions exhibit a rapid and effective topical effect, and effectively deposit the topically active compound for an effective residual effect.

Description

FIELD OF THE INVENTIONThe present invention is directed to compositions, particularly personal care compositions, having an improved ability to deposit topically active compounds on a surface, such as skin or hair. More particularly, the present invention is directed to compositions comprising a topically active compound, a primary surfactant, a hydrotrope, a hydric solvent, an optional cosurfactant, and other optional ingredients. The topically active compounds include antibacterial agents, sunscreens, vitamins, medicaments, fragrance materials, antioxidants, conditioners, emollients, and the like. The topically active compounds typically are insoluble in water, and the compositions deposit the topically active compounds to surfaces more effectively than present-day commercial compositions.BACKGROUND OF THE INVENTIONFor many personal care products, it is desirable not only to provide consumers the basic function of cleansing the skin or hair, but also to deposit a topically active ...

AI Technical Summary

Benefits of technology

A topically active compound is present in a composition of the present invention in an amount of about 0.001% to about 5%, and preferably about 0.01% to about 3%, by weight of the composition. To achieve the full advantage of the present invention, the topically active compound is present in an amount of about 0.05% to about 2%, by weight, of the composition.

, the topically active compound is present in an amount of about 0.05% to about 2%, by weight, of the composition.

The topically active compositions can be ready to use compositions, which typically contain 0.001% to about 2%, preferably 0.01% to about 1.5%, and most preferably about 0.05% to about 1%, of a topically active compound, by weight of the composition. The topically active compositions also can be formulated as concentrates that are diluted before use with one to about 100 parts water to provide an end use composition. The concentrated compositions typically contain greater than about 0.1% and up to about 5%, by weight, of the topically active compound. Applications also are envisioned wherein the end use composition contains greater than 2%, by weight, of the topically active compound.

As discussed above, the absolute amount of topically active compound present in the composition is not as important as the amount of available topically active compound in the composition, and the ability of the composition to rapidly and effectively deposit the topically active compound on a treated surface. The amount of available topically active compound in the composition, and the ability of the composition to deposit the topically active compound, is related to the identity of the surfactant in the composition, the amount of surfactant in the composition, and the presence of optional ingredients in the composition.

For antibacterial agents, to achieve the desired bacteria kill in a short contact time, like 15 to 60 seconds, the continuous aqueous phase of the composition contains an amount of antibacterial agent that is at least about 50%, and preferably at least about 75%, of the saturation concentration of the antibacterial agent in water, when measured at room temperature. To achieve the full advantage of the present invention, the continuous aqueous phase is about 95% to 100% saturated with the antibacterial agent. The amount of antibacterial agent present in the continuous aqueous phase can be defined as the total amount of antibacterial agent in the composition, less any antibacterial agent present in surfactant micelles. The method of determining percent saturation of antibacterial agent in the composition is disclosed hereafter.

To achieve the desired residual activity, the topically active compound is rapidly and effectively deposited on the surface contacted by a composition of the present invention.

Problems solved by technology

Recent publications show that simultaneous cleaning and deposition of topically active ingredients is still a challenge, for example, see U.S. Pat. Nos. 5,885,948; 6,080,707; and 6,080,708.

The need for cleansing compositions that efficiently deposit topically active compounds is magnified when the typically high cost of the topically active compounds is considered, because a substantial portion of these expensive compounds is wasted in present-day compositions.

However, there is a practical limit to incorporating a high level of saturation of active compound with traditional surfactant systems because of cost and / or regulatory constraints.

Because of the high cost of triclosan, such a composition would be too expensive to commercialize.

Physical / chemical modifications of the active compounds, while possibly enhancing deposition, may not be desirable because of additional cost to an already expensive ingredient and / or the need for regulatory reapproval and additional testing required for the modified active compound.

However, this type of composition has limitations.

For example, typical compositions are thickened dispersions, and cannot be used in certain dispensers (e.g., a self-foaming pump).

In addition, some active compounds may not be biologically available on the skin, hair, or other surface when in the form of relatively large hydrophobic droplets or dissolved in a carrier oil.

This strategy also has a limitation of decreased bioavailability when the active compound / deposition aid complex contacts the skin or hair, because the active compound may be less prone to diffuse to the site of action and / or may not be uniformly dispersed over the treated surface.

Most commercial antibacterial compositions, however, generally offer a low to moderate antibacterial activity.

Prior disclosures illustrate attempts to provide such antibacterial compositions, which, to date, do not provide the rapid, broad range control of microorganisms desired by consumers.

It has been difficult to impossible to achieve a high log reduction using an antibacterial composition having a neutral pH of about 5 to about 8, and especially about 6 to about 8.

The compositions disclosed in the Mitchell publication exhibit antibacterial activity in at least 47 minutes contact time, thus the compositions are not highly effective.

Prior disclosures have not addressed the issue of which composition ingredient in an antibacterial composition provides bacterial control.

Prior compositions also have not provided an effective, fast, and broad spectrum control of bacteria at a neutral pH of about 5 to about 8, and especially at about 6 to about 8.

An efficacious antibacterial composition has been difficult to achieve because of the properties of the antibacterial agents and the effects of a surfactant on an antibacterial agent.

However, an increase in solubility of the antimicrobial agent, and in turn, the amount of antibacterial agent in the composition, does not necessarily lead to an increased antibacterial efficacy.

Without being bound to any particular theory, it is theorized that the addition of a surfactant increases antimicrobial agent solubility, but also typically reduces the availability of the antibacterial agent because a surfactant in water forms micelles above the critical micelle concentration of the surfactant.

The antibacterial agent solubilized in the surfactant micelles will control bacteria, but in relatively long time frames.

If the antibacterial agent is tied up in the surfactant micelle (i.e., is not activated), the antibacterial agent is only slowly available and cannot perform its function in a time frame that is practical for cleaning the skin.

In addition, an antibacterial agent solubilized in the micelle is readily washed from the skin during the rinsing process, and is not available to deposit on the skin to provide a residual antibacterial benefit.

Rather, the antibacterial agent is washed away and wasted.

One strategy is to chemically modify the topically active compound, which is not a practical solution to compound deposition.

Dilution deposition involves the use of a topically active compound in a composition that is phase stable during storage and application to the hair, but becomes phase unstable and separates during rinsing.

Images